1080p
From Freepedia
1080p is the shorthand name for a category of video modes. The number 1080 stands for 1080 lines of vertical resolution, while the letter p stands for progressive scan or non-interlaced. 1080p is considered to be an HDTV video mode. The term usually assumes a widescreen aspect ratio of 16:9, implying a horizontal resolution of 1920 lines and a frame resolution of 1920 x 1080 or about 2.07 million pixels. The frame rate in hertz can be either implied by the context or specified after the letter p (such as 1080p30, meaning 30 frames per second).
While 1080p is sometimes referred to in marketing materials as "True High-Definition" or "Full High-Definition", what constitutes high-definition is continually evolving over time.
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Availability
Broadcasts
Even though various television networks in the world broadcast HDTV programming in 1080i and 720p, no 1080p broadcasting actually exists at this time. However, several 1080p resolutions have been standarized for future broadcasting use.
Consumer televisions
There is a limited but growing selection of consumer televisions with native 1080p at this time. In addition, among the television sets with a 1080p resolution, few are actually capable of accepting and reproducing a 1080p input signal, especially via a digital input such as DVI or HDMI. In 2003, Sony released Qualia 004, a 1080p front-projector, while Mitsubishi released a 1080p rear-projection TV; both were based on LCoS technology and had limited availability. Some televisions shown at the January 2005 CES offered 1080p, including sets from Sony, Samsung and Mitsubishi. Samsung's 1080p sets are known to be capable of accepting 1080p over the analog VGA port.
Computer monitors
CRT computer monitors have long been capable of displaying 1080p, albeit as a non-standard resolution since most CRT monitors have an aspect ratio of 4:3. Most 17" computer monitors which support 1280x1024 60hz can be run at 1920x1080p, 60hz using a refresh rate tweaking utility (such as Powerstrip). Some modern widescreen LCD monitors use 1080p as a native mode.
Storage format
Some 1080p and near-1080p content have been released on regular DVD disks using WMV HD compression. These titles can not be played in normal DVD players and can only be viewed on a Windows-based computer with a 3.0Ghz or faster CPU, among other hardware requirements[1].
1080p content is also expected to be released on the upcoming high capacity video disks such as Blu-ray Disc and HD-DVD.
Broadcasting standards
Due to bandwidth limitations of broadcast frequencies, the ATSC and DVB have standardized only the frame rates of 24, 25, and 30 frames per second (1080p24, 1080p25, 1080p30). 1080p30 is currently the most bandwidth-intensive video mode supported by the ATSC. If ATSC's standard MPEG-2 compression is used, higher-framerate versions such as 1080p50 and 1080p60 can only be sent over higher-bandwidth channels; to send these over lower-bandwidth channels, a more modern codec such as the H.264/MPEG-4 AVC codec must be used. Higher frame rates such as 1080p50 and 1080p60 are currently for private or internal use only, and are not part of the broadcasting standard.
The ATSC is considering amending its standard to allow the incorporation of the newer codecs for optional usage; however, this is not expected to result in widespread consumer availability of broadcast 1080p programming, since most of the existing television sets would still only be capable of decoding the older, less-efficient MPEG-2 codec while the bandwidth limitations do not allow for broadcasting two simultaneous streams (i.e. both a 1080i or 720p MPEG-2 stream alongside a 1080p MPEG-4 stream) on the same broadcast channel.
External links
- http://searchsmb.techtarget.com/sDefinition/0,,sid44_gci1071898,00.html
- http://www.pcmag.com/article2/0,1759,1749523,00.asp
See also
| LDTV | 240i60, 288i50 (CIF) |
|---|---|
| SDTV | 480i60 (NTSC), 480p30, 576i50 (PAL, SÉCAM), 576p25 |
| EDTV | 480p60, 576p50, 720i50, 720i60, 720p24, 720p25, 720p30 |
| HDTV | 720p50, 720p60, 1080p24, 1080p25, 1080p30, 1080i50, 1080i60 |
| Progressive, Interlaced | |
| Image:Videores.png | |
